Inside Health

PERSONAL HEALTH

PERSONAL HEALTH; Diabetes Candidates Can Reduce the Risk

By JANE E. BRODY

Published: January 15, 2002

Most serious childhood diseases can now be prevented by vaccines, and most bacterial infections can be cured with antibiotics. But one condition now running rampant has no medical preventive or cure.

That condition is Type 2 diabetes, and preventing and curing it requires a kind of intervention that only the potential and actual victims can provide: making better food choices, getting more exercise and -- most important of all -- avoiding excess weight or taking it off if it's already there.

The incidence of Type 2 diabetes has risen by a third since 1990, and treatment of the disease costs $100 billion a year.

There are now 15 million Americans, including at least 300,000 children, with Type 2 diabetes, an inability to prevent dangerous rises in blood sugar because the body's cells have become resistant to the hormone insulin and the pancreas is unable to supply enough extra to compensate.

One-third of people with this disease do not know they have it. However, like Type 1 diabetes, in which the pancreas fails to produce insulin, Type 2 diabetes can lead to serious, even life-threatening complications, including blindness, kidney disease, nerve damage and heart disease.

Regardless of ethnic heritage, three main groups face an elevated risk of becoming diabetic: those with close blood relatives with diabetes; women who developed gestational diabetes or whose babies weighed more than nine pounds at birth, and people of all ages who are significantly overweight, particularly those with a spare tire around the middle.

Dr. Reza Yavari, an endocrinologist affiliated with the Yale University School of Medicine, said abdominal fat was particularly dangerous ''because it secretes hormones and other factors that counter the action of insulin.''

To determine whether a midlife bulge places you in a high-risk category, take a tape measure and divide your waist size by your hips. If the result exceeds 0.85 for a woman or 1.0 for a man, it is time to think about trimming down that belly.

It does not take much to become a candidate for diabetes. Just eat 100 calories a day more than you expend -- that is about half a Snickers bar -- and in 10 years you will gain 100 extra pounds, Dr. Yavari pointed out.

As the founder of Beyond Care, a lifestyle management program in Branford, Conn., that helps people at risk keep diabetes at bay, Dr. Yavari is painfully aware of how easy it has become for people to overeat and underexercise, starting with the nation's youth. About 85 percent of children with Type 2 diabetes are overweight.

Children today are surrounded by junk food and calorie-laden fast foods even at school, they spend too much time watching television and playing video games and, both in school and at home, they devote too little time to physical activities, Dr. Yavari said.

From 1977 to 1995, for example, walking and cycling among children ages 5 to 15 dropped 40 percent. Fewer than a third now walk to school and participation in sports activities continues to decline, especially as children enter adolescence, when they naturally begin to put on body fat.

Exercise is crucial not only in helping people of all ages maintain a healthy weight, but it also curbs the risk of diabetes by increasing the body's sensitivity to insulin and decreasing the tendency to eat for reasons other than hunger.

The percentage of children who are overweight has risen 50 percent since 1970 -- to about one child in five today -- and, since 1991, adult obesity has risen by about 60 percent.

Excessive television watching is a hazard for adults as well as for children. In a study of 37,918 health professionals released last June, Dr. Frank B. Hu and colleagues at the Harvard School of Public Health found that, compared with men who rarely watched television, those who spent 21 to 40 hours a week watching television faced twice the risk of diabetes and those who watched more than 40 hours a week were nearly three times as likely to develop diabetes.

Those who watched a lot of television also tended to eat more snacks and sweets and fewer fruits and vegetables, adding further to their risk of becoming overweight and developing diabetes.

Of course, women are as susceptible as men to poor health habits that lead to diabetes. In the Nurses Health Study, which has followed nearly 85,000 women for more than 16 years, Dr. Hu reported last June that being overweight was the single most important predictors of diabetes.

Those least likely to develop diabetes were lean, performed moderate to vigorous physical activity at least half an hour a day and ate a healthful diet high in fiber, low in sugars, refined starches and harmful fats. These characteristics were lacking in 90 percent of the 3,300 women who developed Type 2 diabetes in the follow-up period.

Staying Healthy

Last summer, the federal Department of Health and Human Services decided to release the striking results of a national study of diabetes prevention a year ahead of time. The study was conducted at 27 medical centers among 3,234 high-risk participants who had already begun to show an impaired ability to regulate blood sugar.

The study clearly demonstrated that even modest changes in living habits -- eating less fat, exercising two and a half hours a week and losing on average just 7 percent of body weight -- cut the incidence of diabetes by more than half over a three-year period.

The study participants who were most likely to remain healthy were those who attended diet and exercise classes and received monthly professional follow-up coaching to help keep them on track of a healthier lifestyle.

One of the most telling findings of the study was that diet, exercise and weight loss were nearly twice as effective in preventing the onset of diabetes as the drug metformin (Glucophage), which is commonly prescribed for people who are having trouble regulating their blood sugar.

The changes in habits were most effective in people 60 and over, who are little helped by the drug.

The research team, headed by Dr. David M. Nathan of Massachusetts General Hospital in Boston, noted that while most risk factors for diabetes -- age, race, a family history of the disease -- could not be changed, people could control two other factors: obesity and lack of physical activity.

In the classes, participants learned how to read labels and choose and prepare low-fat meals. Most important of all, they learned what makes up a portion of different foods. Many had no idea what a three-ounce serving of meat looks like (a deck of cards).

Rather than insisting that people eliminate high-calorie foods that they enjoyed, the nutrition counselors encouraged consuming these foods less often and in smaller amounts.

For exercise, the counselors emphasized moderate activities like brisk walking for an average of 30 minutes a day. At Beyond Care, Dr. Yavari likes to start out with yoga for overweight, sedentary people, many of whom are in poor physical condition and afraid of exercise.

Through yoga, he said, participants learn to enjoy working out and their fear of exercise diminishes. Then they are ready to take on more vigorous activities.

Chart: ''When Extra Pounds Get Risky'' Being overweight can increase risk of diabetes. To assess your weight, draw lines from your height on the left and weight below and see where they meet. For example, someone 5-foot-8 and 145 pounds (blue lines) is at a healthy weight. Chart shows grid for determining healthy weight by height. (Source: Center for Science in the Public Interest)